Rate-matching around CRS for NR-TDD

ABSTRACT

Rate-matching and channel estimation are disclosed for new radio (NR) user equipments (UEs). An NR UE obtains coexistence information of neighboring legacy operations including common reference signal (CRS) ports, CRS frequency pattern, and a legacy subframe type corresponding to the NR transmission segments. The NR UE determines legacy CRS occasion(s) coinciding with shared downlink direction operations for the NR and legacy operations, and rate-matches reception of NR downlink transmissions around the CRS occasion(s). In other aspects, an NR UE detects overlap of a downlink signal with downlink control channel candidate of a configured control resource set (CORESET). The UE ends monitoring of the candidate within a search space of the CORESET in response to the detected overlap, detects a collision between a scheduled demodulation reference signal (DMRS) and the downlink signal occasion, and discards all or part of the CORESET.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Application No.62/717,440, entitled “RATE-MATCHING AROUND CRS FOR NR-TDD,” filed Aug.10, 2018, the disclosure of which is hereby incorporated herein byreference.

BACKGROUND Field

Aspects of the present disclosure relate generally to wirelesscommunication systems, and to rate-matching around common referencesignals (CRS) for new radio (NR) time division duplex (TDD) operations.

Background

Wireless communication networks are widely deployed to provide variouscommunication services such as voice, video, packet data, messaging,broadcast, and the like. These wireless networks may be multiple-accessnetworks capable of supporting multiple users by sharing the availablenetwork resources. Such networks, which are usually multiple accessnetworks, support communications for multiple users by sharing theavailable network resources. One example of such a network is theUniversal Terrestrial Radio Access Network (UTRAN). The UTRAN is theradio access network (RAN) defined as a part of the Universal MobileTelecommunications System (UMTS), a third generation (3G) mobile phonetechnology supported by the 3rd Generation Partnership Project (3GPP).Examples of multiple-access network formats include Code DivisionMultiple Access (CDMA) networks, Time Division Multiple Access (TDMA)networks, Frequency Division Multiple Access (FDMA) networks, OrthogonalFDMA (OFDMA) networks, and Single-Carrier FDMA (SC-FDMA) networks.

A wireless communication network may include a number of base stationsor node Bs that can support communication for a number of userequipments (UEs). A UE may communicate with a base station via downlinkand uplink. The downlink (or forward link) refers to the communicationlink from the base station to the UE, and the uplink (or reverse link)refers to the communication link from the UE to the base station.

A base station may transmit data and control information on the downlinkto a UE and/or may receive data and control information on the uplinkfrom the UE. On the downlink, a transmission from the base station mayencounter interference due to transmissions from neighbor base stationsor from other wireless radio frequency (RF) transmitters. On the uplink,a transmission from the UE may encounter interference from uplinktransmissions of other UEs communicating with the neighbor base stationsor from other wireless RF transmitters. This interference may degradeperformance on both the downlink and uplink.

As the demand for mobile broadband access continues to increase, thepossibilities of interference and congested networks grows with more UEsaccessing the long-range wireless communication networks and moreshort-range wireless systems being deployed in communities. Research anddevelopment continue to advance wireless technologies not only to meetthe growing demand for mobile broadband access, but to advance andenhance the user experience with mobile communications.

Moreover, advanced radio access technologies (RATs) may be deployed ascosts permit, placing advanced RATs among legacy RATs. In order tominimize the impact on users, as seen from the UE perspective, thecoexistence of the difference RATs may be planned in such a manner toreduce the negative impact of the different technologies on the legacyUEs.

SUMMARY

In one aspect of the disclosure, a method of wireless communicationincludes obtaining, by a user equipment (UE) operating according to anew radio (NR) radio access technology (RAT), coexistence informationassociated with neighboring wireless operations according to a legacyRAT coexisting with the NR RAT, wherein the coexistence informationincludes a number of ports associated with reference signals of thelegacy RAT, a frequency pattern of the reference signals of the legacyRAT, and a subframe type of corresponding subframes of the legacy RATwith transmission segments of the NR RAT, determining, by the UE, one ormore reference signal occasions of the legacy RAT coinciding with shareddownlink direction communication for the NR RAT and legacy RAT, andrate-matching, by the UE, reception of NR downlink transmissions withinthe shared downlink direction communication around the one or morereference signal occasions.

In an additional aspect of the disclosure, an apparatus configured forwireless communication includes means for obtaining, by a UE operatingaccording to a NR RAT, coexistence information associated withneighboring wireless operations according to a legacy RAT coexistingwith the NR RAT, wherein the coexistence information includes a numberof ports associated with reference signals of the legacy RAT, afrequency pattern of the reference signals of the legacy RAT, and asubframe type of corresponding subframes of the legacy RAT withtransmission segments of the NR RAT, means for determining, by the UE,one or more reference signal occasions of the legacy RAT coinciding withshared downlink direction communication for the NR RAT and legacy RAT,and means for rate-matching, by the UE, reception of NR downlinktransmissions within the shared downlink direction communication aroundthe one or more reference signal occasions.

In an additional aspect of the disclosure, a non-transitorycomputer-readable medium having program code recorded thereon. Theprogram code further includes code to obtain, by a UE operatingaccording to a NR RAT, coexistence information associated withneighboring wireless operations according to a legacy RAT coexistingwith the NR RAT, wherein the coexistence information includes a numberof ports associated with reference signals of the legacy RAT, afrequency pattern of the reference signals of the legacy RAT, and asubframe type of corresponding subframes of the legacy RAT withtransmission segments of the NR RAT, code to determine, by the UE, oneor more reference signal occasions of the legacy RAT coinciding withshared downlink direction communication for the NR RAT and legacy RAT,and code to rate-match, by the UE, reception of NR downlinktransmissions within the shared downlink direction communication aroundthe one or more reference signal occasions.

In an additional aspect of the disclosure, an apparatus configured forwireless communication is disclosed. The apparatus includes at least oneprocessor, and a memory coupled to the processor. The processor isconfigured to obtain, by a UE operating according to a NR RAT,coexistence information associated with neighboring wireless operationsaccording to a legacy RAT coexisting with the NR RAT, wherein thecoexistence information includes a number of ports associated withreference signals of the legacy RAT, a frequency pattern of thereference signals of the legacy RAT, and a subframe type ofcorresponding subframes of the legacy RAT with transmission segments ofthe NR RAT, to determine, by the UE, one or more reference signaloccasions of the legacy RAT coinciding with shared downlink directioncommunication for the NR RAT and legacy RAT, and to rate-match, by theUE, reception of NR downlink transmissions within the shared downlinkdirection communication around the one or more reference signaloccasions.

In an additional aspect of the disclosure, a method of wirelesscommunication includes detecting, by a user equipment (UE) operatingaccording to a new radio (NR) radio access technology (RAT), anoverlapping portion of at least one resource element of a downlinkcontrol channel candidate of a configured control resource set (CORESET)overlaps with at least one resource element of a downlink signaloccasion of the NR RAT or a neighboring legacy RAT coexisting with theNR RAT. The method additionally includes ending, by the UE, a monitoringof the downlink control channel candidate within a search space of theconfigured CORESET in response to the detected overlapping portion. Themethod also includes detecting, by the UE, a collision between ascheduled demodulation reference signal (DMRS) within the overlappingportion and the downlink signal occasion, and discarding, by the UE, atleast a portion of the CORESET in response to the detected collision.

In an additional aspect of the disclosure, an apparatus configured forwireless communication includes means for detecting, by a user equipment(UE) operating according to a new radio (NR) radio access technology(RAT), an overlapping portion of at least one resource element of adownlink control channel candidate of a configured control resource set(CORESET) overlaps with at least one resource element of a downlinksignal occasion of the NR RAT or a neighboring legacy RAT coexistingwith the NR RAT. The apparatus additionally includes means for ending,by the UE, a monitoring of the downlink control channel candidate withina search space of the configured CORESET in response to the detectedoverlapping portion. The apparatus also includes means for detecting, bythe UE, a collision between a scheduled demodulation reference signal(DMRS) within the overlapping portion and the downlink signal occasion,and means for discarding, by the UE, at least a portion of the CORESETin response to the detected collision.

In an additional aspect of the disclosure, a non-transitorycomputer-readable medium having program code recorded thereon. Theprogram code includes code to detect, by a user equipment (UE) operatingaccording to a new radio (NR) radio access technology (RAT), anoverlapping portion of at least one resource element of a downlinkcontrol channel candidate of a configured control resource set (CORESET)overlaps with at least one resource element of a downlink signaloccasion of the NR RAT or a neighboring legacy RAT coexisting with theNR RAT. The program code additionally includes code to end, by the UE, amonitoring of the downlink control channel candidate within a searchspace of the configured CORESET in response to the detected overlappingportion. The program code also includes code to detect, by the UE, acollision between a scheduled demodulation reference signal (DMRS)within the overlapping portion and the downlink signal occasion, anddiscard, by the UE, at least a portion of the CORESET in response to thedetected collision.

In an additional aspect of the disclosure, an apparatus configured forwireless communication is disclosed. The apparatus includes at least oneprocessor, and a memory coupled to the processor. The processor isconfigured to detect, by a user equipment (UE) operating according to anew radio (NR) radio access technology (RAT), an overlapping portion ofat least one resource element of a downlink control channel candidate ofa configured control resource set (CORESET) overlaps with at least oneresource element of a downlink signal occasion of the NR RAT or aneighboring legacy RAT coexisting with the NR RAT. The processor isadditionally configured to end, by the UE, a monitoring of the downlinkcontrol channel candidate within a search space of the configuredCORESET in response to the detected overlapping portion. The processoris also configured to detect, by the UE, a collision between a scheduleddemodulation reference signal (DMRS) within the overlapping portion andthe downlink signal occasion, and discard, by the UE, at least a portionof the CORESET in response to the detected collision.

The foregoing has outlined rather broadly the features and technicaladvantages of examples according to the disclosure in order that thedetailed description that follows may be better understood. Additionalfeatures and advantages will be described hereinafter. The conceptionand specific examples disclosed may be readily utilized as a basis formodifying or designing other structures for carrying out the samepurposes of the present disclosure. Such equivalent constructions do notdepart from the scope of the appended claims. Characteristics of theconcepts disclosed herein, both their organization and method ofoperation, together with associated advantages will be better understoodfrom the following description when considered in connection with theaccompanying figures. Each of the figures is provided for the purpose ofillustration and description, and not as a definition of the limits ofthe claims.

BRIEF DESCRIPTION OF THE DRAWINGS

A further understanding of the nature and advantages of the presentdisclosure may be realized by reference to the following drawings. Inthe appended figures, similar components or features may have the samereference label. Further, various components of the same type may bedistinguished by following the reference label by a dash and a secondlabel that distinguishes among the similar components. If just the firstreference label is used in the specification, the description isapplicable to any one of the similar components having the same firstreference label irrespective of the second reference label.

FIG. 1 is a block diagram illustrating details of a wirelesscommunication system.

FIG. 2 is a block diagram illustrating a design of a base station and aUE configured according to one aspect of the present disclosure.

FIG. 3 is a block diagram illustrating a wireless communication systemincluding base stations that use directional wireless beams.

FIG. 4 is a block diagram illustrating example blocks executed toimplement one aspect of the present disclosure.

FIG. 5A is a block diagram illustrating an NR UE configured according toone aspect of the present disclosure.

FIG. 5B is a block diagram illustrating an NR UE, configured accordingto one aspect of the present disclosure, operating in sharedcommunication spectrum with LTE operations that support eIMTA.

FIG. 6 is a block diagram illustrating example blocks executed toimplement one aspect of the present disclosure.

FIG. 7 is a block diagram illustrating an NR UE configured according toone aspect of the present disclosure.

FIG. 8 is a block diagram illustrating an example NR UE configuredaccording to one aspect of the present disclosure.

DETAILED DESCRIPTION

The detailed description set forth below, in connection with theappended drawings, is intended as a description of variousconfigurations and is not intended to limit the scope of the disclosure.Rather, the detailed description includes specific details for thepurpose of providing a thorough understanding of the inventive subjectmatter. It will be apparent to those skilled in the art that thesespecific details are not required in every case and that, in someinstances, well-known structures and components are shown in blockdiagram form for clarity of presentation.

This disclosure relates generally to providing or participating inauthorized shared access between two or more wireless communicationssystems, also referred to as wireless communications networks. Invarious embodiments, the techniques and apparatus may be used forwireless communication networks such as code division multiple access(CDMA) networks, time division multiple access (TDMA) networks,frequency division multiple access (FDMA) networks, orthogonal FDMA(OFDMA) networks, single-carrier FDMA (SC-FDMA) networks, LTE networks,GSM networks, 5^(th) Generation (5G) or new radio (NR) networks, as wellas other communications networks. As described herein, the terms“networks” and “systems” may be used interchangeably.

An OFDMA network may implement a radio technology such as evolved UTRA(E-UTRA), IEEE 802.11, IEEE 802.16, IEEE 802.20, flash-OFDM and thelike. UTRA, E-UTRA, and Global System for Mobile Communications (GSM)are part of universal mobile telecommunication system (UMTS). Inparticular, long term evolution (LTE) is a release of UMTS that usesE-UTRA. UTRA, E-UTRA, GSM, UMTS and LTE are described in documentsprovided from an organization named “3rd Generation Partnership Project”(3GPP), and cdma2000 is described in documents from an organizationnamed “3rd Generation Partnership Project 2” (3GPP2). These variousradio technologies and standards are known or are being developed. Forexample, the 3rd Generation Partnership Project (3GPP) is acollaboration between groups of telecommunications associations thataims to define a globally applicable third generation (3G) mobile phonespecification. 3GPP long term evolution (LTE) is a 3GPP project whichwas aimed at improving the universal mobile telecommunications system(UMTS) mobile phone standard. The 3GPP may define specifications for thenext generation of mobile networks, mobile systems, and mobile devices.The present disclosure is concerned with the evolution of wirelesstechnologies from LTE, 4G, 5G, NR, and beyond with shared access towireless spectrum between networks using a collection of new anddifferent radio access technologies or radio air interfaces.

In particular, 5G networks contemplate diverse deployments, diversespectrum, and diverse services and devices that may be implemented usingan OFDM-based unified, air interface. In order to achieve these goals,further enhancements to LTE and LTE-A are considered in addition todevelopment of the new radio technology for 5G NR networks. The 5G NRwill be capable of scaling to provide coverage (1) to a massive Internetof things (IoTs) with an ultra-high density (e.g., ˜1M nodes/km²),ultra-low complexity (e.g., ˜10 s of bits/sec), ultra-low energy (e.g.,˜10+ years of battery life), and deep coverage with the capability toreach challenging locations; (2) including mission-critical control withstrong security to safeguard sensitive personal, financial, orclassified information, ultra-high reliability (e.g., ˜99.9999%reliability), ultra-low latency (e.g., ˜1 ms), and users with wideranges of mobility or lack thereof; and (3) with enhanced mobilebroadband including extreme high capacity (e.g., ˜10 Tbps/km²), extremedata rates (e.g., multi-Gbps rate, 100+ Mbps user experienced rates),and deep awareness with advanced discovery and optimizations.

The 5G NR may be implemented to use optimized OFDM-based waveforms withscalable numerology and transmission time interval (TTI); having acommon, flexible framework to efficiently multiplex services andfeatures with a dynamic, low-latency time division duplex(TDD)/frequency division duplex (FDD) design; and with advanced wirelesstechnologies, such as massive multiple input, multiple output (MIMO),robust millimeter wave (mmWave) transmissions, advanced channel coding,and device-centric mobility. Scalability of the numerology in 5G NR,with scaling of subcarrier spacing, may efficiently address operatingdiverse services across diverse spectrum and diverse deployments. Forexample, in various outdoor and macro coverage deployments of less than3 GHz FDD/TDD implementations, subcarrier spacing may occur with 15 kHz,for example over 1, 5, 10, 20 MHz, and the like bandwidth. For othervarious outdoor and small cell coverage deployments of TDD greater than3 GHz, subcarrier spacing may occur with 30 kHz over 80/100 MHzbandwidth. For other various indoor wideband implementations, using aTDD over the unlicensed portion of the 5 GHz band, the subcarrierspacing may occur with 60 kHz over a 160 MHz bandwidth. Finally, forvarious deployments transmitting with mmWave components at a TDD of 28GHz, subcarrier spacing may occur with 120 kHz over a 500 MHz bandwidth.

The scalable numerology of the 5G NR facilitates scalable TTI fordiverse latency and quality of service (QoS) requirements. For example,shorter TTI may be used for low latency and high reliability, whilelonger TTI may be used for higher spectral efficiency. The efficientmultiplexing of long and short TTIs to allow transmissions to start onsymbol boundaries. 5G NR also contemplates a self-contained integratedsubframe design with uplink/downlink scheduling information, data, andacknowledgement in the same subframe. The self-contained integratedsubframe supports communications in unlicensed or contention-basedshared spectrum, adaptive uplink/downlink that may be flexiblyconfigured on a per-cell basis to dynamically switch between uplink anddownlink to meet the current traffic needs.

Various other aspects and features of the disclosure are furtherdescribed below. It should be apparent that the teachings herein may beembodied in a wide variety of forms and that any specific structure,function, or both being disclosed herein is merely representative andnot limiting. Based on the teachings herein one of an ordinary level ofskill in the art should appreciate that an aspect disclosed herein maybe implemented independently of any other aspects and that two or moreof these aspects may be combined in various ways. For example, anapparatus may be implemented or a method may be practiced using anynumber of the aspects set forth herein. In addition, such an apparatusmay be implemented or such a method may be practiced using otherstructure, functionality, or structure and functionality in addition toor other than one or more of the aspects set forth herein. For example,a method may be implemented as part of a system, device, apparatus,and/or as instructions stored on a computer readable medium forexecution on a processor or computer. Furthermore, an aspect maycomprise at least one element of a claim.

FIG. 1 is a block diagram illustrating 5G network 100 including variousbase stations and UEs configured according to aspects of the presentdisclosure. The 5G network 100 includes a number of base stations 105and other network entities. A base station may be a station thatcommunicates with the UEs and may also be referred to as an evolved nodeB (eNB), a next generation eNB (gNB), an access point, and the like.Each base station 105 may provide communication coverage for aparticular geographic area. In 3GPP, the term “cell” can refer to thisparticular geographic coverage area of a base station and/or a basestation subsystem serving the coverage area, depending on the context inwhich the term is used.

A base station may provide communication coverage for a macro cell or asmall cell, such as a pico cell or a femto cell, and/or other types ofcell. A macro cell generally covers a relatively large geographic area(e.g., several kilometers in radius) and may allow unrestricted accessby UEs with service subscriptions with the network provider. A smallcell, such as a pico cell, would generally cover a relatively smallergeographic area and may allow unrestricted access by UEs with servicesubscriptions with the network provider. A small cell, such as a femtocell, would also generally cover a relatively small geographic area(e.g., a home) and, in addition to unrestricted access, may also providerestricted access by UEs having an association with the femto cell(e.g., UEs in a closed subscriber group (CSG), UEs for users in thehome, and the like). A base station for a macro cell may be referred toas a macro base station. A base station for a small cell may be referredto as a small cell base station, a pico base station, a femto basestation or a home base station. In the example shown in FIG. 1, the basestations 105 d and 105 e are regular macro base stations, while basestations 105 a-105 c are macro base stations enabled with one of 3dimension (3D), full dimension (FD), or massive MIMO. Base stations 105a-105 c take advantage of their higher dimension MIMO capabilities toexploit 3D beamforming in both elevation and azimuth beamforming toincrease coverage and capacity. Base station 105 f is a small cell basestation which may be a home node or portable access point. A basestation may support one or multiple (e.g., two, three, four, and thelike) cells.

The 5G network 100 may support synchronous or asynchronous operation.For synchronous operation, the base stations may have similar frametiming, and transmissions from different base stations may beapproximately aligned in time. For asynchronous operation, the basestations may have different frame timing, and transmissions fromdifferent base stations may not be aligned in time.

The UEs 115 are dispersed throughout the wireless network 100, and eachUE may be stationary or mobile. A UE may also be referred to as aterminal, a mobile station, a subscriber unit, a station, or the like. AUE may be a cellular phone, a personal digital assistant (PDA), awireless modem, a wireless communication device, a handheld device, atablet computer, a laptop computer, a cordless phone, a wireless localloop (WLL) station, or the like. In one aspect, a UE may be a devicethat includes a Universal Integrated Circuit Card (UICC). In anotheraspect, a UE may be a device that does not include a UICC. In someaspects, UEs that do not include UICCs may also be referred to asinternet of everything (IoE) or internet of things (IoT) devices. UEs115 a-115 d are examples of mobile smart phone-type devices accessing 5Gnetwork 100 A UE may also be a machine specifically configured forconnected communication, including machine type communication (MTC),enhanced MTC (eMTC), narrowband IoT (NB-IoT) and the like. UEs 115 e-115k are examples of various machines configured for communication thataccess 5G network 100. A UE may be able to communicate with any type ofthe base stations, whether macro base station, small cell, or the like.In FIG. 1, a lightning bolt (e.g., communication links) indicateswireless transmissions between a UE and a serving base station, which isa base station designated to serve the UE on the downlink and/or uplink,or desired transmission between base stations, and backhaultransmissions between base stations.

In operation at 5G network 100, base stations 105 a-105 c serve UEs 115a and 115 b using 3D beamforming and coordinated spatial techniques,such as coordinated multipoint (CoMP) or multi-connectivity. Macro basestation 105 d performs backhaul communications with base stations 105a-105 c, as well as small cell, base station 105 f. Macro base station105 d also transmits multicast services which are subscribed to andreceived by UEs 115 c and 115 d. Such multicast services may includemobile television or stream video, or may include other services forproviding community information, such as weather emergencies or alerts,such as Amber alerts or gray alerts.

5G network 100 also support mission critical communications withultra-reliable and redundant links for mission critical devices, such UE115 e, which is a drone. Redundant communication links with UE 115 einclude from macro base stations 105 d and 105 e, as well as small cellbase station 105 f. Other machine type devices, such as UE 115 f(thermometer), UE 115 g (smart meter), and UE 115 h (wearable device)may communicate through 5G network 100 either directly with basestations, such as small cell base station 105 f, and macro base station105 e, or in multi-hop configurations by communicating with another userdevice which relays its information to the network, such as UE 115 fcommunicating temperature measurement information to the smart meter, UE115 g, which is then reported to the network through small cell basestation 105 f. 5G network 100 may also provide additional networkefficiency through dynamic, low-latency TDD/FDD communications, such asin a vehicle-to-vehicle (V2V) mesh network between UEs 115 i-115 kcommunicating with macro base station 105 e.

5G network 100 may also coexist with legacy RATs, such as LTE. Forexample, base station 105 a participates in NR operations including withUE 115 a, while base station 105 d and UE 115 d participate in LTEoperations within the same vicinity and sharing at least downlink bandsor component carriers. The downlink sharing of communication bands maybe invisible to LTE UEs, such as UE 115 d. The NR UE, UE 115 a,determines, according to various aspects of the present disclosure,scheduling within LTE operations in order to rate-match around downlinksignaling from base station 105 d, including common reference signals(CRS), synchronization signal blocks (SSBs), and the like, when both NRand LTE operations share downlink direction access to the communicationband. In order for the NR UE, UE 115 a, to determine the allocateddirection of the LTE subframe according to various aspects of thepresent disclosure, UE 115 a may either receive the additionalinformation, such as uplink/downlink configuration and special subframeformat, to assist in determining the allocated LTE subframe direction,or may operate according to its own allocated slot directioncorresponding to the LTE subframe, when no additional signaling isallowed. Once the corresponding LTE subframe is determined as a downlinkdirection, UE 115 a may rate-match around scheduled downlink signaltransmission.

FIG. 2 shows a block diagram of a design of a base station 105 and a UE115, which may be one of the base station and one of the UEs in FIG. 1.At the base station 105, a transmit processor 220 may receive data froma data source 212 and control information from a controller/processor240. The control information may be for the PBCH, PCFICH, PHICH, PDCCH,EPDCCH, MPDCCH etc. The data may be for the PDSCH, etc. The transmitprocessor 220 may process (e.g., encode and symbol map) the data andcontrol information to obtain data symbols and control symbols,respectively. The transmit processor 220 may also generate referencesymbols, e.g., for the PSS, SSS, and cell-specific reference signal. Atransmit (TX) multiple-input multiple-output (MIMO) processor 230 mayperform spatial processing (e.g., precoding) on the data symbols, thecontrol symbols, and/or the reference symbols, if applicable, and mayprovide output symbol streams to the modulators (MODs) 232 a through 232t. Each modulator 232 may process a respective output symbol stream(e.g., for OFDM, etc.) to obtain an output sample stream. Each modulator232 may further process (e.g., convert to analog, amplify, filter, andupconvert) the output sample stream to obtain a downlink signal.Downlink signals from modulators 232 a through 232 t may be transmittedvia the antennas 234 a through 234 t, respectively.

At the UE 115, the antennas 252 a through 252 r may receive the downlinksignals from the base station 105 and may provide received signals tothe demodulators (DEMODs) 254 a through 254 r, respectively. Eachdemodulator 254 may condition (e.g., filter, amplify, downconvert, anddigitize) a respective received signal to obtain input samples. Eachdemodulator 254 may further process the input samples (e.g., for OFDM,etc.) to obtain received symbols. A MIMO detector 256 may obtainreceived symbols from all the demodulators 254 a through 254 r, performMIMO detection on the received symbols if applicable, and providedetected symbols. A receive processor 258 may process (e.g., demodulate,deinterleave, and decode) the detected symbols, provide decoded data forthe UE 115 to a data sink 260, and provide decoded control informationto a controller/processor 280.

On the uplink, at the UE 115, a transmit processor 264 may receive andprocess data (e.g., for the PUSCH) from a data source 262 and controlinformation (e.g., for the PUCCH) from the controller/processor 280. Thetransmit processor 264 may also generate reference symbols for areference signal. The symbols from the transmit processor 264 may beprecoded by a TX MIMO processor 266 if applicable, further processed bythe modulators 254 a through 254 r (e.g., for SC-FDM, etc.), andtransmitted to the base station 105. At the base station 105, the uplinksignals from the UE 115 may be received by the antennas 234, processedby the demodulators 232, detected by a MIMO detector 236 if applicable,and further processed by a receive processor 238 to obtain decoded dataand control information sent by the UE 115. The processor 238 mayprovide the decoded data to a data sink 239 and the decoded controlinformation to the controller/processor 240.

The controllers/processors 240 and 280 may direct the operation at thebase station 105 and the UE 115, respectively. The controller/processor240 and/or other processors and modules at the base station 105 mayperform or direct the execution of various processes for the techniquesdescribed herein. The controllers/processor 280 and/or other processorsand modules at the UE 115 may also perform or direct the execution ofthe functional blocks illustrated in FIGS. 4 and 6, and/or otherprocesses for the techniques described herein. The memories 242 and 282may store data and program codes for the base station 105 and the UE115, respectively. A scheduler 244 may schedule UEs for datatransmission on the downlink and/or uplink.

Wireless communications systems operated by different network operatingentities (e.g., network operators) may share spectrum. In someinstances, a network operating entity may be configured to use anentirety of a designated shared spectrum for at least a period of timebefore another network operating entity uses the entirety of thedesignated shared spectrum for a different period of time. Thus, inorder to allow network operating entities use of the full designatedshared spectrum, and in order to mitigate interfering communicationsbetween the different network operating entities, certain resources(e.g., time) may be partitioned and allocated to the different networkoperating entities for certain types of communication.

For example, a network operating entity may be allocated certain timeresources reserved for exclusive communication by the network operatingentity using the entirety of the shared spectrum. The network operatingentity may also be allocated other time resources where the entity isgiven priority over other network operating entities to communicateusing the shared spectrum. These time resources, prioritized for use bythe network operating entity, may be utilized by other network operatingentities on an opportunistic basis if the prioritized network operatingentity does not utilize the resources. Additional time resources may beallocated for any network operator to use on an opportunistic basis.

Access to the shared spectrum and the arbitration of time resourcesamong different network operating entities may be centrally controlledby a separate entity, autonomously determined by a predefinedarbitration scheme, or dynamically determined based on interactionsbetween wireless nodes of the network operators.

In some cases, UE 115 and base station 105 may operate in a shared radiofrequency spectrum band, which may include licensed or unlicensed (e.g.,contention-based) frequency spectrum. In an unlicensed frequency portionof the shared radio frequency spectrum band, UEs 115 or base stations105 may traditionally perform a medium-sensing procedure to contend foraccess to the frequency spectrum. For example, UE 115 or base station105 may perform a listen before talk (LBT) procedure such as a clearchannel assessment (CCA) prior to communicating in order to determinewhether the shared channel is available. A CCA may include an energydetection procedure to determine whether there are any other activetransmissions. For example, a device may infer that a change in areceived signal strength indicator (RSSI) of a power meter indicatesthat a channel is occupied. Specifically, signal power that isconcentrated in a certain bandwidth and exceeds a predetermined noisefloor may indicate another wireless transmitter. A CCA also may includedetection of specific sequences that indicate use of the channel. Forexample, another device may transmit a specific preamble prior totransmitting a data sequence. In some cases, an LBT procedure mayinclude a wireless node adjusting its own backoff window based on theamount of energy detected on a channel and/or theacknowledge/negative-acknowledge (ACK/NACK) feedback for its owntransmitted packets as a proxy for collisions.

Use of a medium-sensing procedure to contend for access to an unlicensedshared spectrum may result in communication inefficiencies. This may beparticularly evident when multiple network operating entities (e.g.,network operators) are attempting to access a shared resource. In 5Gnetwork 100, base stations 105 and UEs 115 may be operated by the sameor different network operating entities. In some examples, an individualbase station 105 or UE 115 may be operated by more than one networkoperating entity. In other examples, each base station 105 and UE 115may be operated by a single network operating entity. Requiring eachbase station 105 and UE 115 of different network operating entities tocontend for shared resources may result in increased signaling overheadand communication latency.

FIG. 3 illustrates an example of a timing diagram 300 for coordinatedresource partitioning. The timing diagram 300 includes a superframe 305,which may represent a fixed duration of time (e.g., 20 ms). Superframe305 may be repeated for a given communication session and may be used bya wireless system such as 5G network 100 described with reference toFIG. 1. The superframe 305 may be divided into intervals such as anacquisition interval (A-INT) 310 and an arbitration interval 315. Asdescribed in more detail below, the A-INT 310 and arbitration interval315 may be subdivided into sub-intervals, designated for certainresource types, and allocated to different network operating entities tofacilitate coordinated communications between the different networkoperating entities. For example, the arbitration interval 315 may bedivided into a plurality of sub-intervals 320. Also, the superframe 305may be further divided into a plurality of subframes 325 with a fixedduration (e.g., 1 ms). While timing diagram 300 illustrates threedifferent network operating entities (e.g., Operator A, Operator B,Operator C), the number of network operating entities using thesuperframe 305 for coordinated communications may be greater than orfewer than the number illustrated in timing diagram 300.

The A-INT 310 may be a dedicated interval of the superframe 305 that isreserved for exclusive communications by the network operating entities.In some examples, each network operating entity may be allocated certainresources within the A-INT 310 for exclusive communications. Forexample, resources 330-a may be reserved for exclusive communications byOperator A, such as through base station 105 a, resources 330-b may bereserved for exclusive communications by Operator B, such as throughbase station 105 b, and resources 330-c may be reserved for exclusivecommunications by Operator C, such as through base station 105 c. Sincethe resources 330-a are reserved for exclusive communications byOperator A, neither Operator B nor Operator C can communicate duringresources 330-a, even if Operator A chooses not to communicate duringthose resources. That is, access to exclusive resources is limited tothe designated network operator. Similar restrictions apply to resources330-b for Operator B and resources 330-c for Operator C. The wirelessnodes of Operator A (e.g, UEs 115 or base stations 105) may communicateany information desired during their exclusive resources 330-a, such ascontrol information or data.

When communicating over an exclusive resource, a network operatingentity does not need to perform any medium sensing procedures (e.g.,listen-before-talk (LBT) or clear channel assessment (CCA)) because thenetwork operating entity knows that the resources are reserved. Becauseonly the designated network operating entity may communicate overexclusive resources, there may be a reduced likelihood of interferingcommunications as compared to relying on medium sensing techniques alone(e.g., no hidden node problem). In some examples, the A-INT 310 is usedto transmit control information, such as synchronization signals (e.g.,SYNC signals), system information (e.g., system information blocks(SIBs)), paging information (e.g., physical broadcast channel (PBCH)messages), or random access information (e.g., random access channel(RACH) signals). In some examples, all of the wireless nodes associatedwith a network operating entity may transmit at the same time duringtheir exclusive resources.

In some examples, resources may be classified as prioritized for certainnetwork operating entities. Resources that are assigned with priorityfor a certain network operating entity may be referred to as aguaranteed interval (G-INT) for that network operating entity. Theinterval of resources used by the network operating entity during theG-INT may be referred to as a prioritized sub-interval. For example,resources 335-a may be prioritized for use by Operator A and maytherefore be referred to as a G-INT for Operator A (e.g., G-INT-OpA).Similarly, resources 335-b may be prioritized for Operator B, resources335-c may be prioritized for Operator C, resources 335-d may beprioritized for Operator A, resources 335-e may be prioritized forOperator B, and resources 335-f may be prioritized for operator C.

The various G-INT resources illustrated in FIG. 3 appear to be staggeredto illustrate their association with their respective network operatingentities, but these resources may all be on the same frequencybandwidth. Thus, if viewed along a time-frequency grid, the G-INTresources may appear as a contiguous line within the superframe 305.This partitioning of data may be an example of time divisionmultiplexing (TDM). Also, when resources appear in the same sub-interval(e.g., resources 340-a and resources 335-b), these resources representthe same time resources with respect to the superframe 305 (e.g., theresources occupy the same sub-interval 320), but the resources areseparately designated to illustrate that the same time resources can beclassified differently for different operators.

When resources are assigned with priority for a certain networkoperating entity (e.g., a G-INT), that network operating entity maycommunicate using those resources without having to wait or perform anymedium sensing procedures (e.g., LBT or CCA). For example, the wirelessnodes of Operator A are free to communicate any data or controlinformation during resources 335-a without interference from thewireless nodes of Operator B or Operator C.

A network operating entity may additionally signal to another operatorthat it intends to use a particular G-INT. For example, referring toresources 335-a, Operator A may signal to Operator B and Operator C thatit intends to use resources 335-a. Such signaling may be referred to asan activity indication. Moreover, since Operator A has priority overresources 335-a, Operator A may be considered as a higher priorityoperator than both Operator B and Operator C. However, as discussedabove, Operator A does not have to send signaling to the other networkoperating entities to ensure interference-free transmission duringresources 335-a because the resources 335-a are assigned with priorityto Operator A.

Similarly, a network operating entity may signal to another networkoperating entity that it intends not to use a particular G-INT. Thissignaling may also be referred to as an activity indication. Forexample, referring to resources 335-b, Operator B may signal to OperatorA and Operator C that it intends not to use the resources 335-b forcommunication, even though the resources are assigned with priority toOperator B. With reference to resources 335-b, Operator B may beconsidered a higher priority network operating entity than Operator Aand Operator C. In such cases, Operators A and C may attempt to useresources of sub-interval 320 on an opportunistic basis. Thus, from theperspective of Operator A, the sub-interval 320 that contains resources335-b may be considered an opportunistic interval (O-INT) for Operator A(e.g., O-INT-OpA). For illustrative purposes, resources 340-a mayrepresent the O-INT for Operator A. Also, from the perspective ofOperator C, the same sub-interval 320 may represent an O-INT forOperator C with corresponding resources 340-b. Resources 340-a, 335-b,and 340-b all represent the same time resources (e.g., a particularsub-interval 320), but are identified separately to signify that thesame resources may be considered as a G-INT for some network operatingentities and yet as an O-INT for others.

To utilize resources on an opportunistic basis, Operator A and OperatorC may perform medium-sensing procedures to check for communications on aparticular channel before transmitting data. For example, if Operator Bdecides not to use resources 335-b (e.g., G-INT-OpB), then Operator Amay use those same resources (e.g., represented by resources 340-a) byfirst checking the channel for interference (e.g., LBT) and thentransmitting data if the channel was determined to be clear. Similarly,if Operator C wanted to access resources on an opportunistic basisduring sub-interval 320 (e.g., use an O-INT represented by resources340-b) in response to an indication that Operator B was not going to useits G-INT, Operator C may perform a medium sensing procedure and accessthe resources if available. In some cases, two operators (e.g., OperatorA and Operator C) may attempt to access the same resources, in whichcase the operators may employ contention-based procedures to avoidinterfering communications. The operators may also have sub-prioritiesassigned to them designed to determine which operator may gain access toresources if more than operator is attempting access simultaneously.

In some examples, a network operating entity may intend not to use aparticular G-INT assigned to it, but may not send out an activityindication that conveys the intent not to use the resources. In suchcases, for a particular sub-interval 320, lower priority operatingentities may be configured to monitor the channel to determine whether ahigher priority operating entity is using the resources. If a lowerpriority operating entity determines through LBT or similar method thata higher priority operating entity is not going to use its G-INTresources, then the lower priority operating entities may attempt toaccess the resources on an opportunistic basis as described above.

In some examples, access to a G-INT or O-INT may be preceded by areservation signal (e.g., request-to-send (RTS)/clear-to-send (CTS)),and the contention window (CW) may be randomly chosen between one andthe total number of operating entities.

In some examples, an operating entity may employ or be compatible withcoordinated multipoint (CoMP) communications. For example an operatingentity may employ CoMP and dynamic time division duplex (TDD) in a G-INTand opportunistic CoMP in an O-INT as needed.

In the example illustrated in FIG. 3, each sub-interval 320 includes aG-INT for one of Operator A, B, or C. However, in some cases, one ormore sub-intervals 320 may include resources that are neither reservedfor exclusive use nor reserved for prioritized use (e.g., unassignedresources). Such unassigned resources may be considered an O-INT for anynetwork operating entity, and may be accessed on an opportunistic basisas described above.

In some examples, each subframe 325 may contain 14 symbols (e.g., 250-μsfor 60 kHz tone spacing). These subframes 325 may be standalone,self-contained Interval-Cs (ITCs) or the subframes 325 may be a part ofa long ITC. An ITC may be a self-contained transmission starting with adownlink transmission and ending with a uplink transmission. In someembodiments, an ITC may contain one or more subframes 325 operatingcontiguously upon medium occupation. In some cases, there may be amaximum of eight network operators in an A-INT 310 (e.g., with durationof 2 ms) assuming a 250-μs transmission opportunity.

Although three operators are illustrated in FIG. 3, it should beunderstood that fewer or more network operating entities may beconfigured to operate in a coordinated manner as described above. Insome cases, the location of the G-INT, O-INT, or A-INT within superframe305 for each operator is determined autonomously based on the number ofnetwork operating entities active in a system. For example, if there isonly one network operating entity, each sub-interval 320 may be occupiedby a G-INT for that single network operating entity, or thesub-intervals 320 may alternate between G-INTs for that networkoperating entity and O-INTs to allow other network operating entities toenter. If there are two network operating entities, the sub-intervals320 may alternate between G-INTs for the first network operating entityand G-INTs for the second network operating entity. If there are threenetwork operating entities, the G-INT and O-INTs for each networkoperating entity may be designed as illustrated in FIG. 3. If there arefour network operating entities, the first four sub-intervals 320 mayinclude consecutive G-INTs for the four network operating entities andthe remaining two sub-intervals 320 may contain O-INTs. Similarly, ifthere are five network operating entities, the first five sub-intervals320 may contain consecutive G-INTs for the five network operatingentities and the remaining sub-interval 320 may contain an O-INT. Ifthere are six network operating entities, all six sub-intervals 320 mayinclude consecutive G-INTs for each network operating entity. It shouldbe understood that these examples are for illustrative purposes only andthat other autonomously determined interval allocations may be used.

It should be understood that the coordination framework described withreference to FIG. 3 is for illustration purposes only. For example, theduration of superframe 305 may be more or less than 20 ms. Also, thenumber, duration, and location of sub-intervals 320 and subframes 325may differ from the configuration illustrated. Also, the types ofresource designations (e.g., exclusive, prioritized, unassigned) maydiffer or include more or less sub-designations.

LTE and NR networks may co-exist over the same communication carrier(e.g., downlink band, component carrier, etc.). From the networkperspective, the downlink resources may be shared with someconsiderations. For LTE operation, the UEs may not be impacted by thepresence of NR communications. However, the NR downlink operationsshould rate-match around some of the LTE system downlink signals, suchas common reference signal (CRS), channel state information (CSI)reference signals (CSI-RS), and the like. LTE and NR users may shareresources and parameters, such as the number of CRS ports, the frequencyshift values (e.g., v_shift values), and subframe types (e.g., MBSFN vs.non-MBSFN), through configuration. Thus, in frequency division duplex(FDD) bands, the NR users may be aware of the exact resource elements(REs) used for LTE CRS. However, without obtaining additionalinformation exchange or defining proper UE behavior, NR UEs may notcurrently perform such rate-matching around CRS REs in time divisionduplex (TDD) bands. For example, in order to rate-match around LTE CRS,an NR UE should know the TDD downlink/uplink configuration, the specialsubframe (SSF) format, such as the number of downlink symbols (DwPTS),uplink symbols (UpPTS), and guard periods (GPs). Additionally, ifenhanced interference mitigation and traffic adaptation (eIMTA) issupported, even more information would be useful for an NR user torate-match around TDD CRS REs. Various aspects of the present disclosureprovide for NR UEs to determine locations of TDD CRS REs forrate-matching.

FIG. 4 is a block diagram illustrating example blocks executed toimplement one aspect of the present disclosure. The example blocks willalso be described with respect to NR UE 115 a as illustrated in FIG. 8.FIG. 8 is a block diagram illustrating NR UE 115 a configured accordingto one aspect of the present disclosure. NR UE 115 a includes thestructure, hardware, and components as illustrated for UE 115 of FIG. 2.For example, NR UE 115 a includes controller/processor 280, whichoperates to execute logic or computer instructions stored in memory 282,as well as controlling the components of NR UE 115 a that provide thefeatures and functionality of NR UE 115 a. NR UE 1158, under control ofcontroller/processor 280, transmits and receives signals via wirelessradios 800 a-r and antennas 252 a-r. Wireless radios 800 a-r includesvarious components and hardware, as illustrated in FIG. 2 for UE 115,including modulator/demodulators 254 a-r, MIMO detector 256, receiveprocessor 258, transmit processor 264, and TX MIMO processor 266.

At block 400, an NR UE obtains coexistence information associated withneighboring legacy RAT wireless operations. In one example aspect, thelegacy RAT may be LTE operations. The coexistence information mayinclude parameters related to CRS, such as the number of portsassociated with the CRS, the frequency shift pattern of the CRS (e.g.,v_shift values), and a subframe type of the corresponding LTE subframes(e.g., multicast-broadcast single frequency network (MBSFN) subframesvs. non-MBSFN subframes). MBSFN subframes may only have CRS transmittedduring the first symbol (symbol 0). NR UE 115 a receives the coexistenceinformation via antennas 252 a-r and wireless radios 800 a-r and storesthe parameters, under control of controller/processor 280, in memory 282at coexistence information 801.

At block 401, the NR UE determines one or more reference signaloccasions of the legacy RAT coinciding with shared downlink directioncommunications. While the parameters known at coexistence information801 provides enough information for NR UE 115 a to identify locations ofthe downlink signals (e.g., CRS, CRS-RS, etc.) transmitted by an LTEbase station operating in frequency division duplex (FDD) bands, NR UE115 a cannot specifically determine the location of downlink signaltransmission occasions in time division duplex (TDD) bands withouteither obtaining additional information or specific UE behaviors todetermine the reference signal transmission occasions with enoughspecificity to successfully rate match around. Accordingly, variousaspects of the present disclosure determine the one or more referencesignal occasions in TDD bands either through receipt of additionalsignaling or by defining such behaviors, such as presuming an LTEsubframe direction based on the granted allocation direction for NRoperations. NR UE 115 a, under control of controller/processor 280,would use such additional signaling or UE behaviors in addition to theparameters in coexistence information 801 to determine the referencesignal occasions of the legacy RAT (e.g., LTE).

At block 402, the NR UE rate-matches one or more reference signaloccasions of the legacy RAT coinciding with shared downlink directioncommunications. After determining the locations of the one or morereference signal transmission occasions, NR UE 115 a, under control ofcontroller/processor 280, executes rate-matching logic 803, stored inmemory 282.

The execution environment of rate-matching logic 803 controls NR UE 115a to rate-match any reception of NR downlink transmissions around theLTE downlink signals (e.g., CRS, CRS-RS, etc.).

FIG. 5A is a block diagram illustrating NR UE 115 a configured accordingto one aspect of the present disclosure. NR UE 115 a participates incommunications using a 5G NR RAT via NR base station 105 a (e.g., gNB).The communication stream 51, between NR UE 115 a and base station 105 a,coexists over the same band or component carriers as the legacy TDD LTERAT communications via communication stream 50 between legacy UE 115 dand legacy base station 105 d. In order to reduce the impact of NRoperations on any LTE operations between legacy UE 115 a and legacy basestation 105 d, NR UE 115 a would rate-match around some types of LTEdownlink signals (e.g., CRS, CRS-RS, etc.).

Various aspects of the present disclosure provide for CRS rate-matchingby NR UEs, such as NR UE 105 a, in TDD bands, in which the NR UEs areeither allowed to receive additional signaling or where no additionalsignaling is allowed. NR UE 115 a would determine the shared downlinkdirection communication regions 500, in which LTE subframes are eitherconfigured in the downlink direction or, for special subframes, havedownlink pilot time slot (DwPTS) symbols 501 corresponding to NRdownlink configured transmission slots. Legacy base station 105 wouldhave downlink signals scheduled, such as CRS, at predeterminedlocations, depending on the uplink-downlink configuration and specialsubframe format assigned. NR UE 105 a may determine such predeterminedlocations and rate-match reception of NR downlink communications aroundsuch LTE downlink signaling.

Where additional signaling would be allowed, the TDD downlink/uplinkconfiguration and SSF format can be indicated to NR UE 115 a via radioresource control (RRC) signaling from NR base station 105 a. Once thisadditional information is available to NR UE 115 a, NR UE 115 a canrate-match around the TDD CRS REs within shared downlink directioncommunication regions 500. In operation, the indication of additionalsignaling transmitted from NR base station 105 a to NR UE 115 a shouldbe such that the NR UE 115 a would know the mapping between the LTEsubframes of communication stream 50 and the NR slots of communicationstream 51, as well as the mapping between the MBSFN subframes and NRslots.

FIG. 5B is a block diagram illustrating NR UE 115, configured accordingto one aspect of the present disclosure, operating in sharedcommunication spectrum with LTE operations that support eIMTA. eIMTA, ingeneral, allows a cell or cluster of cells to dynamically adaptuplink/downlink subframe resources based on the actual traffic needs.For example, cells can use downlink-heavy configurations when downlinktraffic is heavy and uplink-heavy configurations when uplink traffic isheavy. For TDD eIMTA, these uplink/downlink configurations can beconfigured such that a baseline configuration (e.g., uplink-heavy) maybe signaled using system broadcast signals (e.g., SIB, MIB), whileupdated configurations (e.g., downlink HARQ reference uplink/downlinkconfigurations or downlink-heavy) may be semi-statically signaled usingRRC. Moreover, uplink/downlink configuration changes may be dynamicallysignaled using layer 1 (L1) reconfiguration signals, such as viadownlink control information (DCI) signals and the like.

It should be noted that according to eIMTA procedures uplink and specialsubframes can be dynamically reconfigured to downlink subframes, butdownlink subframes may not be dynamically reconfigured to uplink orspecial subframes.

The communication stream, such as communication stream 52, configured tosupport eIMTA includes anchor subframes (e.g., subframes 0, 1, 2, and5), which are common subframes across the baseline and updatedconfigurations, and non-anchor subframes (e.g., subframes 3, 4, 6, 7, 8,and 9) which may adaptively change between special/uplink and downlinkdirection in response to dynamic L1 signaling. The direction or categoryof anchor subframes may not be dynamically changed. Where eIMTA issupported, even more information may be included or supplemented to theadditional signaling solutions to allow NR UE 115 a to identify andrate-match around LTE-based downlink signals (e.g., CRS, CRS-RS, etc.).For example, in LTE operations between legacy base station 105 d andlegacy UE 115 d, legacy base station 105 d broadcasts the baselineuplink/downlink configuration that identifies the direction of thesubframes (e.g., uplink, downlink, or special) and identifies which ofthe subframes are anchor subframes and which are not. This baselineconfiguration may be broadcast within a system broadcast, such as SIB 1.As traffic conditions change, legacy base station 105 d maysemi-statically update the uplink/downlink configuration via RRCsignaling. The semi-static update may update the underlyinguplink/downlink configuration, including identification ofanchor/non-anchor subframes and direction, or may simply update thedirection of non-anchor subframes of the baseline configuration.

NR UE 115 a may receive this baseline or semi-statically updatedconfiguration information in order to understand which of the LTEsubframes are anchor subframes, whose direction cannot be changeddynamically. However, at this stage, NR UE 115 a may not be aware of anydynamic change of direction that has occurred in the non-anchorsubframes. Various aspects of the present disclosure as illustrated inFIG. 5B provide for alternative options for indicating the dynamicchange of directions over the non-anchor subframes to the NR users.

For example, in a first alternative aspect, NR UE 115 a may monitor anddecode the LTE group common PDCCH transmitted from legacy base station105 d. The LTE group common PDCCH, which may include L1 signaling, suchas DCI, provides an indication of any dynamic direction changes for thenon-anchor subframes (e.g., subframes 3, 4, 6, 7, 8, and 9). In a secondalternative aspect, NR UE 115 a may monitor and decode the NR PDCCHtransmitted from NR base station 105 a. This NR PDCCH specificallyincludes the dynamic signaling that identifies any dynamic change ofdirection of the non-anchor LTE subframes of communication stream 52. NRbase station 105 a may obtain the dynamic signaling information in anumber of different ways, including via backhaul 502 directly fromlegacy base station 105 d, or by monitoring and receiving the signalingfrom legacy base station 105 d over the air.

A third alternative aspect provides for NR UE 115 a to follow its ownscheduling to determine the direction of the non-anchor subframes. Thus,when NR UE 115 a receives an uplink grant or allocation for a slotwithin communication stream 51, it will assume the correspondingnon-anchor subframe in communication stream 52 is also an uplinksubframe in which case no rate-matching will be performed. Otherwise,when NR UE 115 a receives a downlink grant or allocation for a slotwithin communication stream 51, it will assume the correspondingnon-anchor subframe in communication stream 52 is a downlink subframe,thus, triggering the rate-matching around CRS REs in that downlinksubframe.

Thus, in operations as illustrated in FIG. 5B according to one aspect ofthe present disclosure that allows additional signaling, NR UE 115 afirst receives signaling identifying the semi-static uplink/downlinkconfiguration, which identifies the anchor and non-anchor subframes incommunication stream 52. NR UE 115 a may then obtain the dynamicsignaling information, as described in one of the three alternativeaspects above, to determine the current subframe category/direction foreach of the non-anchor subframes in communication stream 52. NR UE 115 adetermines the shared downlink direction communication regions 500, inwhich both its slot direction of communication stream 51 and thesubframe direction of communication stream 52 are downlink, and performsrate-matching around any LTE downlink signaling that may come fromlegacy base station 105 d at known locations. As illustrated, thedynamic signaling identifies subframe 3 as an uplink direction, andsubframes 4, 6, 7, 8, and, 9 as downlink direction. Thus, NR UE 115 awill not perform rate-matching either in region 503, as subframe 3 is inan uplink direction, or, at least for the uplink slots of communicationstream 51 within regions 504 and 505.

For downlink sharing in 5G NR operations, introduction of additionalsignaling may not be an option. In such cases, it may be possible forthe NR UE to assume a DL/UL direction of the LTE operation, but in inother cases the direction of the LTE may not be assumed. Whether the NRUE performs rate matching may be based on the UL/DL direction of the NRoperation and the assumed UL/DL or unknown direction of the LTEoperation. For example, when the NR operation direction is UL and theassumed LTE operation direction is UL, then the NR UE does not performrate matching. However, when the NR operation direction is UL and theassumed LTE operation direction is DL, then the NR UE does perform ratematching. When the NR operation direction is UL and the direction of theLTE operation is not known (e.g., in LTE SSF), then the NR UE may eitherperform rate matching or not perform rate matching. Additionally, whenthe NR operation direction is DL and the assumed LTE operation directionis DL, then the NR UE does perform rate matching. However, when the NRoperation direction is DL and the assumed LTE operation direction is UL,then the NR UE does not perform rate matching. When the NR operationdirection is DL and the direction of the LTE operation is not known,then the NR UE may either perform rate matching or not perform ratematching.

From the forgoing, it should be evident that the NR UE 115 a may followits own scheduling whether the LTE operation supports eIMTA, as in FIG.5B or not, as in FIG. 5A. For example, when NR UE 115 a receives anuplink grant over a given slot or a portion of a slot of communicationstream 51, no rate-matching would be needed. Otherwise, where NR UE 115a receives a downlink grant over a given slot or a portion of a slot ofcommunication stream 51, it assumes that the corresponding LTE subframeon communication stream 50 (non-eIMTA) or communication stream 52(eIMTA) is also configured for downlink. Because downlink signals, suchas CRS symbols, will be at a fixed location in both downlink subframesand the downlink portion of the special subframes, regardless of thespecial subframe format, NR UE 115 a can rate-match around the assumeddownlink signals.

In one example implementation illustrated in FIG. 5B, the NR downlinkallocation of communication stream 51 spans over symbols 0-7. Regardlessof whether this downlink allocation spans an LTE downlink subframe, suchas subframe 0, or the downlink symbols of a special subframe, such asspecial subframe 1, CRS, for example, may be transmitted over symbols 0,1, 4, 7, where a 3/4-port CRS is configured, or symbols 0, 4 and 7,where a 1/2-port CRS is configured. The consequence of this approach isthat, even when the LTE portion is in uplink, NR UE 115 might stillincorrectly assume a downlink direction based on its own scheduling andrate-match around non-existent CRSs. However, the complexity ofoperations within NR UE 115 is reduced without sacrificing an impact onthe legacy LTE operations.

In another alternative aspect, generally, a base station may select thesame or at least a similar downlink/uplink configuration for both NR andLTE operations for the purpose of facilitating downlink sharing.Referring back to FIG. 5A, when NR UE 115 a does not receive anyadditional signaling for rate-matching purposes, it can compare its NRTDD slot configuration of communication stream 51 with the multipleavailable LTE TDD configurations. NR UE 115 a may assume and identifythe LTE TDD configuration that communication stream 50 is estimated tobe configured with is the one that is most similar to its own NR TDDslot configuration. There may be differences in the configurations, suchas where the special subframe (e.g., special subframes 1 and 6) may belocated, but, according to the presently described example aspect, NR UE115 a will rate-match according to the joint direction, when thedirections are the same between the NR and LTE configurations (e.g.,rate-match when both directions are downlink and not rate-match whenboth directions are uplink), or according to the direction granted to NRUE 115 a when the directions of both operations do not match. Thedescribed example aspect may be more efficient in operations that do notsupport eIMTA, as illustrated in FIG. 5A, as NR UE 115 a would notperform rate-matching when LTE operations are not assumed in thedownlink direction.

It should be noted that where the NR semi-static TDD slot configurationdoes not exactly match one of the available LTE TDD configurations, NRUE 115 a may rate-match around the assumed CRS locations when thegranted downlink for NR UE 115 a is within the portion that is notmatched with LTE TDD configuration.

Additional aspects of the present disclosure may provide differentmechanisms for an NR UE, such as NR UE 115 a, to determine the framestructure used by the LTE operations. For example, in a firstalternative aspect without additional signaling, NR UE 115 a (FIG. 5A)may derive the same frame structure (e.g., FDD, TDD, unlicensedspectrum, etc.) based on the band being used for the NR and LTEoperations. NR UE 115 a identifies the shared band or component carriershared for NR and LTE operations. The identified band may, accordingly,be known to NR UE 115 a to be associated with a particular framestructure (e.g., FDD, TDD, unlicensed, or the like).

A second alternative aspect may include the availability of additionalsignaling. In such alternative aspect, NR UE 115 a may receive a signalthat indicates the frame structure, and, if TDD, may still furtherinclude additional information to identify the TDD uplink/downlinkconfiguration. Still further additional signaling for TDD framestructures may be used to indicate the special subframe format or toindicate particular configurations that impact CRS configurations. Forexample, instead of a signal indicating between 10 different specialsubframe configurations, the signal may indicate a subset of types ofCRS configurations that would impact the CRS configuration (e.g., CRS inthe first 3 control symbols, CRS up to first slot, CRS within the first9 symbols, and CRS in the first 12 symbols). Signaling may also indicatethat CRS is not present in special subframes (e.g., special subframeformat #10, in which there are no CRS outside of the CRS in symbol 0).Thus, depending on the level of additional information to be includedwith regard to frame structure and the like, the additional signalingmay include one or more bits to accommodate conveying the information.

In general, for sharing of downlink resources between NR and LTEoperations, an NR UE will rate-match around LTE downlink signals, suchas CRS, CSI-RS, and the like, in both FDD and TDD bands. In operationsfor PDCCH decoding, when the NR UE monitors a PDCCH candidate in asearch space set occasion of a particular slot, if at least one RE of aPDCCH candidate on the serving cell overlaps with at least one REallocated for downlink signals (e.g., NR synchronization signal block(SSB), LTE CRS, or the like), then the NR UE may not be required tomonitor the PDCCH candidate any further in order to rate-match aroundthe downlink signal. When the parameter identifying the precoder RBgrouping (e.g., precoderGranularity) is set to be all contiguous RBs,all of the RBs in that given cluster may have the same precoding. Insuch a configuration, an NR UE will not expect to be configured with aset of resource blocks of a control resource set (CORESET) that includesmore than four subsets of resource blocks that are not contiguous infrequency. A CORESET includes a collection of resource blocks over whichthe NR UE's search space is defined. Each CORESET may have up to fourclusters when wideband demodulation reference signal (WB DMRS) isconfigured, in which each cluster comprises a number of consecutiveresource blocks. The aforementioned precoder RB grouping parameteridentifies a number of consecutive resource blocks in a cluster that mayhave the same precoding.

FIG. 6 is a block diagram illustrating example blocks executed toimplement one aspect of the present disclosure. The example blocks willalso be described with respect to NR UE 115 a as illustrated in FIG. 8.FIG. 8 is a block diagram illustrating NR UE 115 a configured accordingto one aspect of the present disclosure. NR UE 115 a includes thestructure, hardware, and components as illustrated for UE 115 of FIG. 2.For example, NR UE 115 a includes controller/processor 280, whichoperates to execute logic or computer instructions stored in memory 282,as well as controlling the components of NR UE 115 a that provide thefeatures and functionality of NR UE 115 a. NR UE 115 a, under control ofcontroller/processor 280, transmits and receives signals via wirelessradios 800 a-r and antennas 252 a-r. Wireless radios 800 a-r includesvarious components and hardware, as illustrated in FIG. 2 for UE 115,including modulator/demodulators 254 a-r, MIMO detector 256, receiveprocessor 258, transmit processor 264, and TX MIMO processor 266.

At block 600, an NR UE detects an overlapping portion of at least oneresource element of a downlink control channel candidate that overlapswith at least one resource element of a downlink signal occasion ofeither NR operations or a neighboring legacy RAT coexisting with the NRRAT. An NR cluster may be determined by an NR UE to overlap the LTE bandbased on multiple different considerations. For example, in a firstalternative, an NR UE may determine an overlapping portion to includethe portion in which NR DMRS RE(s) collide with NR SSB or LTE CRS RE(s).Alternatively, the NR UE may determine the overlapping portion toinclude the NR RB(s) that contain at least one demodulation referencesignal (DMRS) RE that collides with an NR SSB or LTE CRS RE.Alternatively still, the NR UE may determine the overlapping portion toinclude segment(s) of contiguous NR RBs in which each such segmentcontains RBs defined by the precoder size parameter that have at leastone DRMS RE which collides with an NR SSB or LTE-CRS RE. NR UE 115 a,under control of controller/processor 280, executes signal overlap logic804, stored in memory 282. The execution environment of signal overlaplogic 804 controls NR UE 115 a to detect the overlapping portion asdescribed herein.

Because an NR PDCCH candidate occupies all control symbols within asearch space set occasion of the CORESET, all symbols can be discardedas a result of one symbol being discarded for the PDCCH candidate.Therefore for channel estimation, an NR UE may also choose to discardall symbols over the frequency range corresponding to the overlappingportion, as defined in the various alternatives above.

The NR UE may further alternatively determine the overlapping portion asa set of NR DMRS RE(s) that collide with either NR SSB or LTE CRS RE(s),and then extend this set to also include NR DMRS RE(s) with a same setof RE indices in all of the symbols in the same search space setoccasion. A further alternative option may provide for the NR UE todetermine the overlapping portion as a set of NR RB(s) that contain atleast one DMRS RE that collides with an NR SSB or LTE CRS RE, and thenextend this set to include all of the NR RB(s) with a same set of RBindices in all of the symbols in the same search space set occasion. Afurther additional option may provide for the NR UE to determine theoverlapping portion as a set of segment(s) of contiguous NR RBs in whicheach segment containing RBs that are defined by the precoder sizeparameter has at least one DRMS RE colliding with an NR SSB or LTE CRSRE, and then extending this set to include all NR RBs with a same set ofRB indices as the segment(s) of contiguous NR RBs in all symbols in asame search space set occasion.

At block 601, the NR UE ends monitoring of the downlink control channelcandidate within a search space of a configured CORESET in response tothe detected overlapping portion. Once the NR UE detects or determinesan overlapping portion in which some portion of the DMRS overlaps with ascheduled downlink signal, such as an LTE CRS, NR SSB, or the like, theNR UE may discontinue the blind decode monitoring of the PDCCH candidateand rate-match around the scheduled downlink signal. NR UE 115 a, undercontrol of controller/processor 280, executes signal overlap logic 804,stored in memory 282. The execution environment of signal overlap logic804 controls NR UE 115 a to end monitoring of the NR PDCCH candidate asdescribed herein.

At block 602, the NR UE detects a collision between a scheduled NR DMRSwithin the overlapping portion and the downlink signal occasion. Whilethe NR UE may stop monitoring the PDCCH candidate to rate-match aroundthe downlink signal, there may still be scheduled, NR-based DMRStransmissions during the overlapping portion of the NR cluster. When apotential collision is detected between the scheduled NR DMRS and an LTEdownlink signal, the NR DMRS and, at block 603, the NR UE discards atleast a portion of the CORESET in response to the detected collision. NRUE 115 a, under control of controller/processor 280, executes collisionmaintenance logic 805, stored in memory 282. The execution environmentof collision maintenance logic 805 controls NR UE 115 a to detect thedetect the collision and discard at least the portion of the CORESET asdescribed herein.

FIG. 7 is a block diagram illustrating an NR UE 115 a configuredaccording to one aspect of the present disclosure. NR communicationsoccur over NR band 71 between NR base station 105 a and NR UE 115 a,while LTE communications occur over LTE band 70 between legacy basestation 105 d and UE 115 a. The NR and LTE operations coexist withsharing of downlink resources over the same band or component carrier.LTE transmissions 700 may occur over LTE REs while NR cluster 701overlaps over a portion of LTE transmissions 700. LTE downlink signals(e.g., CRS, CSI-RS, etc.) may exist in LTE transmissions 700 thatoverlaps NR cluster 701 in overlapping portion 702. NR downlink signals(e.g., SSB) may also exist in overlapping portion 702 of NR cluster 701.Based on current operations, if there is any NR candidate, such as PDCCHcandidate 705, within overlapping portion 701, and any of its REscollide with any downlink signals, NR candidate 705 may be discarded.However, DMRS 706 may also be scheduled over NR cluster 701. If DMRS 706collides with NR SSB or LTE CRS on any RE, DMRS 706 will not betransmitted by NR base station 105 a. Instead, base station 105 dtransmits the downlink signals resulting in any DMRS-based channelestimation being corrupted. In such a case, a first alternative solutionprovides for overlapping portion 702 of NR cluster 701 may be discarded.This, however, may create two clusters (clusters 703 and 704) out of asingle previous cluster, which is not desirable. A second alternativesolution provides for discarding all of NR cluster 701. A thirdalternative solution provides for an expectation that NR UE 115 a is notconfigured with a cluster for which DMRS 706 collides with any downlinksignaling, such as LTE CRS and/or NR SSB.

Those of skill in the art would understand that information and signalsmay be represented using any of a variety of different technologies andtechniques. For example, data, instructions, commands, information,signals, bits, symbols, and chips that may be referenced throughout theabove description may be represented by voltages, currents,electromagnetic waves, magnetic fields or particles, optical fields orparticles, or any combination thereof.

The functional blocks and modules in FIGS. 4 and 6 may compriseprocessors, electronics devices, hardware devices, electronicscomponents, logical circuits, memories, software codes, firmware codes,etc., or any combination thereof.

Those of skill would further appreciate that the various illustrativelogical blocks, modules, circuits, and algorithm steps described inconnection with the disclosure herein may be implemented as electronichardware, computer software, or combinations of both. To clearlyillustrate this interchangeability of hardware and software, variousillustrative components, blocks, modules, circuits, and steps have beendescribed above generally in terms of their functionality. Whether suchfunctionality is implemented as hardware or software depends upon theparticular application and design constraints imposed on the overallsystem. Skilled artisans may implement the described functionality invarying ways for each particular application, but such implementationdecisions should not be interpreted as causing a departure from thescope of the present disclosure. Skilled artisans will also readilyrecognize that the order or combination of components, methods, orinteractions that are described herein are merely examples and that thecomponents, methods, or interactions of the various aspects of thepresent disclosure may be combined or performed in ways other than thoseillustrated and described herein.

The various illustrative logical blocks, modules, and circuits describedin connection with the disclosure herein may be implemented or performedwith a general-purpose processor, a digital signal processor (DSP), anapplication specific integrated circuit (ASIC), a field programmablegate array (FPGA) or other programmable logic device, discrete gate ortransistor logic, discrete hardware components, or any combinationthereof designed to perform the functions described herein. Ageneral-purpose processor may be a microprocessor, but in thealternative, the processor may be any conventional processor,controller, microcontroller, or state machine. A processor may also beimplemented as a combination of computing devices, e.g., a combinationof a DSP and a microprocessor, a plurality of microprocessors, one ormore microprocessors in conjunction with a DSP core, or any other suchconfiguration.

The steps of a method or algorithm described in connection with thedisclosure herein may be embodied directly in hardware, in a softwaremodule executed by a processor, or in a combination of the two. Asoftware module may reside in RAM memory, flash memory, ROM memory,EPROM memory, EEPROM memory, registers, hard disk, a removable disk, aCD-ROM, or any other form of storage medium known in the art. Anexemplary storage medium is coupled to the processor such that theprocessor can read information from, and write information to, thestorage medium. In the alternative, the storage medium may be integralto the processor. The processor and the storage medium may reside in anASIC. The ASIC may reside in a user terminal. In the alternative, theprocessor and the storage medium may reside as discrete components in auser terminal.

In one or more exemplary designs, the functions described may beimplemented in hardware, software, firmware, or any combination thereof.If implemented in software, the functions may be stored on ortransmitted over as one or more instructions or code on acomputer-readable medium. Computer-readable media includes both computerstorage media and communication media including any medium thatfacilitates transfer of a computer program from one place to another.Computer-readable storage media may be any available media that can beaccessed by a general purpose or special purpose computer. By way ofexample, and not limitation, such computer-readable media can compriseRAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic diskstorage or other magnetic storage devices, or any other medium that canbe used to carry or store desired program code means in the form ofinstructions or data structures and that can be accessed by ageneral-purpose or special-purpose computer, or a general-purpose orspecial-purpose processor. Also, a connection may be properly termed acomputer-readable medium. For example, if the software is transmittedfrom a website, server, or other remote source using a coaxial cable,fiber optic cable, twisted pair, or digital subscriber line (DSL), thenthe coaxial cable, fiber optic cable, twisted pair, or DSL, are includedin the definition of medium. Disk and disc, as used herein, includescompact disc (CD), laser disc, optical disc, digital versatile disc(DVD), floppy disk and blu-ray disc where disks usually reproduce datamagnetically, while discs reproduce data optically with lasers.Combinations of the above should also be included within the scope ofcomputer-readable media.

As used herein, including in the claims, the term “and/or,” when used ina list of two or more items, means that any one of the listed items canbe employed by itself, or any combination of two or more of the listeditems can be employed. For example, if a composition is described ascontaining components A, B, and/or C, the composition can contain Aalone; B alone; C alone; A and B in combination; A and C in combination;B and C in combination; or A, B, and C in combination. Also, as usedherein, including in the claims, “or” as used in a list of itemsprefaced by “at least one of” indicates a disjunctive list such that,for example, a list of “at least one of A, B, or C” means A or B or C orAB or AC or BC or ABC (i.e., A and B and C) or any of these in anycombination thereof.

The previous description of the disclosure is provided to enable anyperson skilled in the art to make or use the disclosure. Variousmodifications to the disclosure will be readily apparent to thoseskilled in the art, and the generic principles defined herein may beapplied to other variations without departing from the spirit or scopeof the disclosure. Thus, the disclosure is not intended to be limited tothe examples and designs described herein but is to be accorded thewidest scope consistent with the principles and novel features disclosedherein.

What is claimed is:
 1. A method of wireless communication, comprising:detecting, by a user equipment (UE) operating according to a new radio(NR) radio access technology (RAT), an overlapping portion of at leastone resource element of a downlink control channel candidate of aconfigured control resource set (CORESET) overlaps with at least oneresource element of a downlink signal occasion of the NR RAT or aneighboring legacy RAT coexisting with the NR RAT; ending, by the UE, amonitoring of the downlink control channel candidate within a searchspace of the configured CORESET in response to the detected overlappingportion; detecting, by the UE, a collision between a scheduleddemodulation reference signal (DMRS) within the overlapping portion andthe downlink signal occasion; and discarding, by the UE, at least aportion of the CORESET in response to the detected collision.
 2. Themethod of claim 1, wherein the detecting the overlapping portionincludes one of: detecting at least one resource element of an NRscheduled DMRS colliding with the at least one resource element of thedownlink signal occasion; detecting at least one NR resource block thatincludes at least one resource element of the NR scheduled DMRScolliding with the at least one resource element of the downlink signaloccasion; or detecting one or more segments of a plurality of contiguousNR resource blocks that include at least one resource block defined by aprecoder size parameter to have at least one resource element of the NRscheduled DMRS colliding with the at least one resource element of thedownlink signal occasion.
 3. The method of claim 2, wherein thedetecting the at least one resource element of the NR scheduled DMRSincludes: detecting at least one resource element of the NR scheduledDMRS colliding with the at least one resource element of the downlinksignal occasion; and detecting the at least one resource element of theNR scheduled DMRS having a same set of resource element indices in allsymbols within a same search space set occasion.
 4. The method of claim2, wherein the detecting the NR resource block includes: detecting theat least one NR resource block that includes the at least one resourceelement of the NR scheduled DMRS colliding with the at least oneresource element of the downlink signal occasion; and detecting the atleast one NR resource block having a same set of resource block indicesin all symbols within a same search space set occasion.
 5. The method ofclaim 2, wherein the detecting the NR resource block includes: detectingthe one or more segments of the plurality of contiguous NR resourceblocks that include the at least one resource block defined by theprecoder size parameter to have the at least one resource element of theNR scheduled DMRS colliding with the at least one resource element ofthe downlink signal occasion; and detecting the at least one NR resourceblock having the same set of resource block indices as the one or moresegments of the plurality of contiguous NR resource blocks in allsymbols within a same search space set occasion.
 6. The method of claim1, wherein the discarding the at least a portion of the CORESET includesone of: discarding the overlapping portion; or discarding a clusterhaving the overlapping portion.
 7. The method of claim 6, wherein amaximum number of clusters of resource blocks with contiguous DMRSresource elements across resource blocks fails to exceed a preconfiguredmaximum limit of clusters of contiguous resource blocks after thediscarding the overlapping portion.
 8. The method of claim 1, whereinthe downlink signal occasion includes one of: a common reference signalof the legacy RAT; or a synchronization signal block of the NR RAT. 9.The method of claim 1, wherein the configured CORESET has a maximumnumber of clusters of resource blocks with contiguous DMRS resourceelements such that no resource element of the downlink signal occasioncandidate of the CORESET overlaps with any resource element of thedownlink signal occasion.
 10. An apparatus configured for wirelesscommunication, comprising: means for detecting, by a user equipment (UE)operating according to a new radio (NR) radio access technology (RAT),an overlapping portion of at least one resource element of a downlinkcontrol channel candidate of a configured control resource set (CORESET)overlaps with at least one resource element of a downlink signaloccasion of the NR RAT or a neighboring legacy RAT coexisting with theNR RAT; means for ending, by the UE, a monitoring of the downlinkcontrol channel candidate within a search space of the configuredCORESET in response to the detected overlapping portion; means fordetecting, by the UE, a collision between a scheduled demodulationreference signal (DMRS) within the overlapping portion and the downlinksignal occasion; and means for discarding, by the UE, at least a portionof the CORESET in response to the detected collision.
 11. The apparatusof claim 10, wherein the means for detecting the overlapping portionincludes one of: means for detecting at least one resource element of anNR scheduled DMRS colliding with the at least one resource element ofthe downlink signal occasion; means for detecting at least one NRresource block that includes at least one resource element of the NRscheduled DMRS colliding with the at least one resource element of thedownlink signal occasion; or means for detecting one or more segments ofa plurality of contiguous NR resource blocks that include at least oneresource block defined by a precoder size parameter to have at least oneresource element of the NR scheduled DMRS colliding with the at leastone resource element of the downlink signal occasion.
 12. The apparatusof claim 11, wherein the means for detecting the at least one resourceelement of the NR scheduled DMRS includes: means for detecting at leastone resource element of the NR scheduled DMRS colliding with the atleast one resource element of the downlink signal occasion; and meansfor detecting the at least one resource element of the NR scheduled DMRShaving a same set of resource element indices in all symbols within asame search space set occasion.
 13. The apparatus of claim 11, whereinthe means for detecting the NR resource block includes: means fordetecting the at least one NR resource block that includes the at leastone resource element of the NR scheduled DMRS colliding with the atleast one resource element of the downlink signal occasion; and meansfor detecting the at least one NR resource block having a same set ofresource block indices in all symbols within a same search space setoccasion.
 14. The apparatus of claim 11, wherein the means for detectingthe NR resource block includes: means for detecting the one or moresegments of the plurality of contiguous NR resource blocks that includethe at least one resource block defined by the precoder size parameterto have the at least one resource element of the NR scheduled DMRScolliding with the at least one resource element of the downlink signaloccasion; and means for detecting the at least one NR resource blockhaving the same set of resource block indices as the one or moresegments of the plurality of contiguous NR resource blocks in allsymbols within a same search space set occasion.
 15. The apparatus ofclaim 10, wherein the means for discarding the at least a portion of theCORESET includes one of: means for discarding the overlapping portion;or means for discarding a cluster having the overlapping portion. 16.The apparatus of claim 15, wherein a maximum number of clusters ofresource blocks with contiguous DMRS resource elements across resourceblocks fails to exceed a preconfigured maximum limit of clusters ofcontiguous resource blocks after the discarding the overlapping portion.17. The apparatus of claim 10, wherein the downlink signal occasionincludes one of: a common reference signal of the legacy RAT; or asynchronization signal block of the NR RAT.
 18. A non-transitorycomputer-readable medium having program code recorded thereon, theprogram code comprising: program code executable by a computer forcausing the computer to detect, by a user equipment (UE) operatingaccording to a new radio (NR) radio access technology (RAT), anoverlapping portion of at least one resource element of a downlinkcontrol channel candidate of a configured control resource set (CORESET)overlaps with at least one resource element of a downlink signaloccasion of the NR RAT or a neighboring legacy RAT coexisting with theNR RAT; program code executable by the computer for causing the computerto end, by the UE, a monitoring of the downlink control channelcandidate within a search space of the configured CORESET in response tothe detected overlapping portion; program code executable by thecomputer for causing the computer to detect, by the UE, a collisionbetween a scheduled demodulation reference signal (DMRS) within theoverlapping portion and the downlink signal occasion; and program codeexecutable by the computer for causing the computer to discard, by theUE, at least a portion of the CORESET in response to the detectedcollision.
 19. The non-transitory computer-readable medium of claim 18,wherein the program code executable by the computer for causing thecomputer to detect the overlapping portion includes one of: program codeexecutable by the computer for causing the computer to detect at leastone resource element of an NR scheduled DMRS colliding with the at leastone resource element of the downlink signal occasion; program codeexecutable by the computer for causing the computer to detect at leastone NR resource block that includes at least one resource element of theNR scheduled DMRS colliding with the at least one resource element ofthe downlink signal occasion; or program code executable by the computerfor causing the computer to detect one or more segments of a pluralityof contiguous NR resource blocks that include at least one resourceblock defined by a precoder size parameter to have at least one resourceelement of the NR scheduled DMRS colliding with the at least oneresource element of the downlink signal occasion.
 20. The non-transitorycomputer-readable medium of claim 19, wherein the program codeexecutable by the computer for causing the computer to detect the atleast one resource element of the NR scheduled DMRS includes: programcode executable by the computer for causing the computer to detect atleast one resource element of the NR scheduled DMRS colliding with theat least one resource element of the downlink signal occasion; andprogram code executable by the computer for causing the computer todetect the at least one resource element of the NR scheduled DMRS havinga same set of resource element indices in all symbols within a samesearch space set occasion.
 21. The non-transitory computer-readablemedium of claim 19, wherein the program code executable by the computerfor causing the computer to detect the NR resource block includes:program code executable by the computer for causing the computer todetect the at least one NR resource block that includes the at least oneresource element of the NR scheduled DMRS colliding with the at leastone resource element of the downlink signal occasion; and program codeexecutable by the computer for causing the computer to detect the atleast one NR resource block having a same set of resource block indicesin all symbols within a same search space set occasion.
 22. Thenon-transitory computer-readable medium of claim 19, wherein the programcode executable by the computer for causing the computer to detect theNR resource block includes: program code executable by the computer forcausing the computer to detect the one or more segments of the pluralityof contiguous NR resource blocks that include the at least one resourceblock defined by the precoder size parameter to have the at least oneresource element of the NR scheduled DMRS colliding with the at leastone resource element of the downlink signal occasion; and program codeexecutable by the computer for causing the computer to detect the atleast one NR resource block having the same set of resource blockindices as the one or more segments of the plurality of contiguous NRresource blocks in all symbols within a same search space set occasion.23. The non-transitory computer-readable medium of claim 18, wherein theprogram code executable by the computer for causing the computer todiscard the at least a portion of the CORESET includes one of: programcode executable by the computer for causing the computer to discard theoverlapping portion; or program code executable by the computer forcausing the computer to discard a cluster having the overlappingportion.
 24. The non-transitory computer-readable medium of claim 23,wherein a maximum number of clusters of resource blocks with contiguousDMRS resource elements across resource blocks fails to exceed apreconfigured maximum limit of clusters of contiguous resource blocksafter the discarding the overlapping portion.
 25. The non-transitorycomputer-readable medium of claim 18, wherein the downlink signaloccasion includes one of: a common reference signal of the legacy RAT;or a synchronization signal block of the NR RAT.
 26. An apparatusconfigured for wireless communication, the apparatus comprising: atleast one processor; and a memory coupled to the at least one processor,wherein the at least one processor is configured to: detect, by a userequipment (UE) operating according to a new radio (NR) radio accesstechnology (RAT), an overlapping portion of at least one resourceelement of a downlink control channel candidate of a configured controlresource set (CORESET) overlaps with at least one resource element of adownlink signal occasion of the NR RAT or a neighboring legacy RATcoexisting with the NR RAT; end, by the UE, a monitoring of the downlinkcontrol channel candidate within a search space of the configuredCORESET in response to the detected overlapping portion; detect, by theUE, a collision between a scheduled demodulation reference signal (DMRS)within the overlapping portion and the downlink signal occasion; anddiscard, by the UE, at least a portion of the CORESET in response to thedetected collision.
 27. The apparatus of claim 26, wherein the whereinthe at least one processor is configured to detect the overlappingportion by one of: detecting at least one resource element of an NRscheduled DMRS colliding with the at least one resource element of thedownlink signal occasion; detecting at least one NR resource block thatincludes at least one resource element of the NR scheduled DMRScolliding with the at least one resource element of the downlink signaloccasion; or detecting one or more segments of a plurality of contiguousNR resource blocks that include at least one resource block defined by aprecoder size parameter to have at least one resource element of the NRscheduled DMRS colliding with the at least one resource element of thedownlink signal occasion.
 28. The apparatus of claim 27, wherein thewherein the at least one processor is configured to detect the at leastone resource element of the NR scheduled DMRS by: detecting at least oneresource element of the NR scheduled DMRS colliding with the at leastone resource element of the downlink signal occasion; and detecting theat least one resource element of the NR scheduled DMRS having a same setof resource element indices in all symbols within a same search spaceset occasion.
 29. The apparatus of claim 27, wherein the wherein the atleast one processor is configured to detect the NR resource block by:detecting the at least one NR resource block that includes the at leastone resource element of the NR scheduled DMRS colliding with the atleast one resource element of the downlink signal occasion; anddetecting the at least one NR resource block having a same set ofresource block indices in all symbols within a same search space setoccasion.
 30. The apparatus of claim 27, wherein the wherein the atleast one processor is configured to detect the NR resource block by:detecting the one or more segments of the plurality of contiguous NRresource blocks that include the at least one resource block defined bythe precoder size parameter to have the at least one resource element ofthe NR scheduled DMRS colliding with the at least one resource elementof the downlink signal occasion; and detecting the at least one NRresource block having the same set of resource block indices as the oneor more segments of the plurality of contiguous NR resource blocks inall symbols within a same search space set occasion.
 31. The apparatusof claim 27, wherein the wherein the at least one processor isconfigured to discard the at least a portion of the CORESET by one of:discarding the overlapping portion; or discarding a cluster having theoverlapping portion.
 32. The apparatus of claim 31, wherein a maximumnumber of clusters of resource blocks with contiguous DMRS resourceelements across resource blocks fails to exceed a preconfigured maximumlimit of clusters of contiguous resource blocks after the discarding theoverlapping portion.
 33. The apparatus of claim 26, wherein the downlinksignal occasion includes one of: a common reference signal of the legacyRAT; or a synchronization signal block of the NR RAT.